/**
 * *****************************************************************************
 * Copyright 2011 See AUTHORS file.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 *****************************************************************************
 */
package sg.atom.utils.datastructure.collection.primitives;

import java.util.Arrays;
import sg.atom.utils.math.AtomFastMath;

/**
 * A resizable, ordered or unordered float array. Avoids the boxing that occurs
 * with ArrayList<Float>. If unordered, this class avoids a memory copy when
 * removing elements (the last element is moved to the removed element's
 * position).
 *
 * @author Nathan Sweet
 */
public class FloatArray {

    public float[] items;
    public int size;
    public boolean ordered;

    /**
     * Creates an ordered array with a capacity of 16.
     */
    public FloatArray() {
        this(true, 16);
    }

    /**
     * Creates an ordered array with the specified capacity.
     */
    public FloatArray(int capacity) {
        this(true, capacity);
    }

    /**
     * @param ordered If false, methods that remove elements may change the
     * order of other elements in the array, which avoids a memory copy.
     * @param capacity Any elements added beyond this will cause the backing
     * array to be grown.
     */
    public FloatArray(boolean ordered, int capacity) {
        this.ordered = ordered;
        items = new float[capacity];
    }

    /**
     * Creates a new array containing the elements in the specific array. The
     * new array will be ordered if the specific array is ordered. The capacity
     * is set to the number of elements, so any subsequent elements added will
     * cause the backing array to be grown.
     */
    public FloatArray(FloatArray array) {
        this.ordered = array.ordered;
        size = array.size;
        items = new float[size];
        System.arraycopy(array.items, 0, items, 0, size);
    }

    /**
     * Creates a new ordered array containing the elements in the specified
     * array. The capacity is set to the number of elements, so any subsequent
     * elements added will cause the backing array to be grown.
     */
    public FloatArray(float[] array) {
        this(true, array, 0, array.length);
    }

    /**
     * Creates a new array containing the elements in the specified array. The
     * capacity is set to the number of elements, so any subsequent elements
     * added will cause the backing array to be grown.
     *
     * @param ordered If false, methods that remove elements may change the
     * order of other elements in the array, which avoids a memory copy.
     */
    public FloatArray(boolean ordered, float[] array, int startIndex, int count) {
        this(ordered, count);
        size = count;
        System.arraycopy(array, startIndex, items, 0, count);
    }

    public void add(float value) {
        float[] items = this.items;
        if (size == items.length) {
            items = resize(Math.max(8, (int) (size * 1.75f)));
        }
        items[size++] = value;
    }

    public void addAll(FloatArray array) {
        addAll(array, 0, array.size);
    }

    public void addAll(FloatArray array, int offset, int length) {
        if (offset + length > array.size) {
            throw new IllegalArgumentException("offset + length must be <= size: " + offset + " + " + length + " <= " + array.size);
        }
        addAll(array.items, offset, length);
    }

    public void addAll(float... array) {
        addAll(array, 0, array.length);
    }

    public void addAll(float[] array, int offset, int length) {
        float[] items = this.items;
        int sizeNeeded = size + length;
        if (sizeNeeded > items.length) {
            items = resize(Math.max(8, (int) (sizeNeeded * 1.75f)));
        }
        System.arraycopy(array, offset, items, size, length);
        size += length;
    }

    public float get(int index) {
        if (index >= size) {
            throw new IndexOutOfBoundsException("index can't be >= size: " + index + " >= " + size);
        }
        return items[index];
    }

    public void set(int index, float value) {
        if (index >= size) {
            throw new IndexOutOfBoundsException("index can't be >= size: " + index + " >= " + size);
        }
        items[index] = value;
    }

    public void incr(int index, float value) {
        if (index >= size) {
            throw new IndexOutOfBoundsException("index can't be >= size: " + index + " >= " + size);
        }
        items[index] += value;
    }

    public void mul(int index, float value) {
        if (index >= size) {
            throw new IndexOutOfBoundsException("index can't be >= size: " + index + " >= " + size);
        }
        items[index] *= value;
    }

    public void insert(int index, float value) {
        if (index > size) {
            throw new IndexOutOfBoundsException("index can't be > size: " + index + " > " + size);
        }
        float[] items = this.items;
        if (size == items.length) {
            items = resize(Math.max(8, (int) (size * 1.75f)));
        }
        if (ordered) {
            System.arraycopy(items, index, items, index + 1, size - index);
        } else {
            items[size] = items[index];
        }
        size++;
        items[index] = value;
    }

    public void swap(int first, int second) {
        if (first >= size) {
            throw new IndexOutOfBoundsException("first can't be >= size: " + first + " >= " + size);
        }
        if (second >= size) {
            throw new IndexOutOfBoundsException("second can't be >= size: " + second + " >= " + size);
        }
        float[] items = this.items;
        float firstValue = items[first];
        items[first] = items[second];
        items[second] = firstValue;
    }

    public boolean contains(float value) {
        int i = size - 1;
        float[] items = this.items;
        while (i >= 0) {
            if (items[i--] == value) {
                return true;
            }
        }
        return false;
    }

    public int indexOf(float value) {
        float[] items = this.items;
        for (int i = 0, n = size; i < n; i++) {
            if (items[i] == value) {
                return i;
            }
        }
        return -1;
    }

    public int lastIndexOf(char value) {
        float[] items = this.items;
        for (int i = size - 1; i >= 0; i--) {
            if (items[i] == value) {
                return i;
            }
        }
        return -1;
    }

    public boolean removeValue(float value) {
        float[] items = this.items;
        for (int i = 0, n = size; i < n; i++) {
            if (items[i] == value) {
                removeIndex(i);
                return true;
            }
        }
        return false;
    }

    /**
     * Removes and returns the item at the specified index.
     */
    public float removeIndex(int index) {
        if (index >= size) {
            throw new IndexOutOfBoundsException("index can't be >= size: " + index + " >= " + size);
        }
        float[] items = this.items;
        float value = items[index];
        size--;
        if (ordered) {
            System.arraycopy(items, index + 1, items, index, size - index);
        } else {
            items[index] = items[size];
        }
        return value;
    }

    /**
     * Removes from this array all of elements contained in the specified array.
     *
     * @return true if this array was modified.
     */
    public boolean removeAll(FloatArray array) {
        int size = this.size;
        int startSize = size;
        float[] items = this.items;
        for (int i = 0, n = array.size; i < n; i++) {
            float item = array.get(i);
            for (int ii = 0; ii < size; ii++) {
                if (item == items[ii]) {
                    removeIndex(ii);
                    size--;
                    break;
                }
            }
        }
        return size != startSize;
    }

    /**
     * Removes and returns the last item.
     */
    public float pop() {
        return items[--size];
    }

    /**
     * Returns the last item.
     */
    public float peek() {
        return items[size - 1];
    }

    /**
     * Returns the first item.
     */
    public float first() {
        if (size == 0) {
            throw new IllegalStateException("Array is empty.");
        }
        return items[0];
    }

    public void clear() {
        size = 0;
    }

    /**
     * Reduces the size of the backing array to the size of the actual items.
     * This is useful to release memory when many items have been removed, or if
     * it is known that more items will not be added.
     */
    public void shrink() {
        if (items.length == size) {
            return;
        }
        resize(size);
    }

    /**
     * Increases the size of the backing array to acommodate the specified
     * number of additional items. Useful before adding many items to avoid
     * multiple backing array resizes.
     *
     * @return {@link #items}
     */
    public float[] ensureCapacity(int additionalCapacity) {
        int sizeNeeded = size + additionalCapacity;
        if (sizeNeeded > items.length) {
            resize(Math.max(8, sizeNeeded));
        }
        return items;
    }

    protected float[] resize(int newSize) {
        float[] newItems = new float[newSize];
        float[] items = this.items;
        System.arraycopy(items, 0, newItems, 0, Math.min(size, newItems.length));
        this.items = newItems;
        return newItems;
    }

    public void sort() {
        Arrays.sort(items, 0, size);
    }

    public void reverse() {
        float[] items = this.items;
        for (int i = 0, lastIndex = size - 1, n = size / 2; i < n; i++) {
            int ii = lastIndex - i;
            float temp = items[i];
            items[i] = items[ii];
            items[ii] = temp;
        }
    }

    public void shuffle() {
        float[] items = this.items;
        for (int i = size - 1; i >= 0; i--) {
            int ii = AtomFastMath.random(i);
            float temp = items[i];
            items[i] = items[ii];
            items[ii] = temp;
        }
    }

    /**
     * Reduces the size of the array to the specified size. If the array is
     * already smaller than the specified size, no action is taken.
     */
    public void truncate(int newSize) {
        if (size > newSize) {
            size = newSize;
        }
    }

    /**
     * Returns a random item from the array, or zero if the array is empty.
     */
    public float random() {
        if (size == 0) {
            return 0;
        }
        return items[AtomFastMath.random(0, size - 1)];
    }

    public float[] toArray() {
        float[] array = new float[size];
        System.arraycopy(items, 0, array, 0, size);
        return array;
    }

    public boolean equals(Object object) {
        if (object == this) {
            return true;
        }
        if (!(object instanceof FloatArray)) {
            return false;
        }
        FloatArray array = (FloatArray) object;
        int n = size;
        if (n != array.size) {
            return false;
        }
        float[] items = this.items;
        float[] arrayItems = array.items;
        for (int i = 0; i < n; i++) {
            if (items[i] != arrayItems[i]) {
                return false;
            }
        }
        return true;
    }

    public boolean equals(Object object, float epsilon) {
        if (object == this) {
            return true;
        }
        if (!(object instanceof FloatArray)) {
            return false;
        }
        FloatArray array = (FloatArray) object;
        int n = size;
        if (n != array.size) {
            return false;
        }
        float[] items = this.items;
        float[] arrayItems = array.items;
        for (int i = 0; i < n; i++) {
            if (Math.abs(items[i] - arrayItems[i]) > epsilon) {
                return false;
            }
        }
        return true;
    }

    public String toString() {
        if (size == 0) {
            return "[]";
        }
        float[] items = this.items;
        StringBuilder buffer = new StringBuilder(32);
        buffer.append('[');
        buffer.append(items[0]);
        for (int i = 1; i < size; i++) {
            buffer.append(", ");
            buffer.append(items[i]);
        }
        buffer.append(']');
        return buffer.toString();
    }

    public String toString(String separator) {
        if (size == 0) {
            return "";
        }
        float[] items = this.items;
        StringBuilder buffer = new StringBuilder(32);
        buffer.append(items[0]);
        for (int i = 1; i < size; i++) {
            buffer.append(separator);
            buffer.append(items[i]);
        }
        return buffer.toString();
    }
}
